Mitsubishi Repair: 99 montro sport 3.0 4wd, transmission control unit, mitsubishi dealership

Question
Hi anthony,
i do have a 1999 montro  sport the transmissoin does not shift on D 4TH GEAR I HAVE TO PUT IT ON D1 OR 2 SO THE TRANSMISSON CAN SIFT,i took it to amco they told me it need new trans they rebuilt it and a few days later went to pick it up and i have been told it did not solve the problem and they think it is a wiring problem and they do not know where is the problem and how to fix it , i took it to a few trans shop not even one has any idea what is the problem please let me know if u get any problem like this befor and what might case it
thanks again and i hope to hear from u soon
best
john

Answer
John,
Your mechanic should check the car's transmission control unit (TCU).  It's the computer that controls the shifting of the transmission. It the TCU is damaged, you will have the problems you're describing.  If none of the transmission shops are able to check the TCU, I would recommend bringing your car to your nearest Mitsubishi dealership to diagnose it.  It may be as simple as a worn wiring harness, or as bad a burnt out TCU.  But have those items checked out.
Good luck!